1. Field of the Invention
This invention relates to a structure for a variable electronic component, such as variable resistor or variable capacitor, wherein a certain parameter or physical property of the component is adjusted by rotating a rotor relative to a substrate.
2. Description of the Prior Art
A variable resistor of the above-described type is disclosed in Japanese Utility Model Application Laid-open No. 3-85604 (Laid-open: Aug. 29, 1991) of the same applicant. The resistor comprises an insulating substrate formed with a resistor strip, and a rotor rotatably supported on the substrate. The rotor has a contact portion in pressing and sliding contact with the resistor strip, so that the resistance of the resistor is adjustable by turning the rotor relative to the substrate.
The rotor of the prior art variable resistor is formed with a plurality of engaging slots for engagement with a turning tool, such as a driver, which is incorporated in an automatic adjusting apparatus. After mounting the resistor at a suitable portion of a printed circuit board, the driver of the automatic adjusting apparatus is axially aligned with the rotational center of the rotor. Then, the driver is lowered for engagement with the engaging slots to enable rotation of the rotor for resistance adjustment.
However, if the driver is not properly positioned rotationally, it is impossible to bring the driver into complete engagement with the engaging slots of the rotor. Thus, the rotational position of the driver must be finely adjusted before actually turning the rotor, consequently resulting in a deterioration of the efficiency in automatic resistance adjustment.